1. Field of the Invention
This invention is in the field of hydrogen extraction reformers (U.S. Class 48/61, Int. Class B01J) having means for providing relative rotary motion between a portion of the reformer and a fuel to create Taylor Vortex Flows (TVF) that accelerate chemical reactions and sequester contaminants.
2. Description of Related Art
Hydrogen extraction reformers, also known as fuel processors, fuel reformers or reformers, are used to extract hydrogen from hydrocarbon fuels such as methane (CH4), methanol (CH3OH), ethanol (C2H5OH), propane (C3H8), butane (C4H10), octane (C8H18), kerosene (C12H26) and gasoline as well as other hydrogen-bearing chemicals such as ammonia (NH3) and sodium borohydride (NaBH4). Hydrogen gas is extracted for a number of uses including lighting, chemical manufacturing and fuel for electrochemical fuel cells that generate electricity—as disclosed in Case A, cited above—as well as conventional fuel cells.
Extraction of hydrogen has been accomplished by several methods. Pyrolysis or “cracking” uses catalysts at high temperatures to force breakage of hydrogen bonds to other elements. Chemical processes at lower temperatures use additional agents and a catalyst to promote disassociation. Examples of the latter such as steam-reforming or partial oxidation use heat and water to promote oxidation reactions such as CH4+3H2O→CO+3H2+2H2O or CH3OH+H20→2H2+2CO usually followed by the water shift reaction, CO+H2O→H2+CO2. All these reactions are reversible and do not go to completion in either direction unless one of the constituents (e.g. H2) is continuously removed from the reformer. This occurs in direct internal reformulation (DIR) where H2 is extracted as soon as it is separated to be used as fuel in a fuel cell (Case A) or conveyed to external storage from a stand alone reformer.
The most environmentally benign of the reformer processes is pyrolysis, which generates hydrogen gas containing carbon as soot (C). Other reforming processes, such as steam reforming, produce carbon monoxide (CO) or carbon dioxide (CO2) as environmental contaminants in various concentrations depending upon specific attributes of the process employed. These gasses can poison catalysts.
Where fuel contains sulphur (S), sulphur or its compounds also become additional contaminants. Even where sulphur contaminants are present in low concentrations, they can foul or destroy catalysts and other components in chemical reactors. The same is true for free carbon. Some fuel cells chemical processes cannot tolerate even minute amounts of carbon, carbon monoxide, carbon dioxide or sulphur oxides so their reformers require external purifiers that add cost and complexity to the reformers.
Reformers have been a subject of continuous engineering and improvement for over one-hundred years. Objectives include a) higher reaction rates b) further elimination of contaminants without need of external purifiers, c) reduction of capital and operating costs, especially in connection with catalyst maintenance and d) diminution in size.